Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
249 views
in Technique[技术] by (71.8m points)

php - Checking for empty arrays: count vs empty

This question on 'How to tell if a PHP array is empty' had me thinking of this question

Is there a reason that count should be used instead of empty when determining if an array is empty or not?

My personal thought would be if the 2 are equivalent for the case of empty arrays you should use empty because it gives a boolean answer to a boolean question. From the question linked above, it seems that count($var) == 0 is the popular method. To me, while technically correct, makes no sense. E.g. Q: $var, are you empty? A: 7. Hmmm...

Is there a reason I should use count == 0 instead or just a matter of personal taste?

As pointed out by others in comments for a now deleted answer, count will have performance impacts for large arrays because it will have to count all elements, whereas empty can stop as soon as it knows it isn't empty. So, if they give the same results in this case, but count is potentially inefficient, why would we ever use count($var) == 0?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)

I generally use empty. Im not sure why people would use count really - If the array is large then count takes longer/has more overhead. If you simply need to know whether or not the array is empty then use empty.


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...